Collapsible paperboard box



Oct. 31, 1944. s. L. COHEN ET AL COLLAPSIBLE PAPER BOARD BOX Original Filed Jan. 2, 1941 INVENTORS .5amueLb.00/ze;z, M02" 9L ATTORN Patented Oct-31, 1944 S PATENT OFFICE coLLArsrBLE PAPERBOARD Box Samuel L. Cohen and Morton J. Margolies, Brooklyn, N. Y.

.Original application January 2, 1941, Serial No.

Divided and this application February 5, 194? Serial No. 474,802

4 Claims.

The present invention is concerned with col-v lapsible boxes especially of the corrugated board type.

It is among the objects of said 1nvent1on to provide a box of the above type which may be economically made of a single blank, which may be easily and quickl setup, which affords an unusually strong structure capable of carrying substantial weight upon its bottom, in which, in fact, the weight carried thereby inherently strengthens the interlock of the constituent flaps of the bottom, which affords a flat outer bottom structure that lends itself readily to mailing packages and which cannot be collapsed by a mere thrust thereon, but which box may readily be collapsed by appropriate simple manipulation when required. l

In the accompanyingdrawingin which is shown one of Variouspossible embodiments of the several features of the invention,

Fig. 1 is a plan view of the blank from which the box is made, l

Fig. 2 is a perspective view of the box, showing the manner of setting up the bottom thereof,

Fig. 3 is a perspective view of the set up box showing the appearance of the underside thereof when set up, w l

Fig. 4 is a transverse sectional view taken on line 44 of Fig. 3, showing the inner plan view of the box bottom, and

Fig. 5 is a detail perspective of a detail.

This is a division of our parent application, Serial No. 372,858, filed January 2, 1941.

Referring now to the drawing, the box, which is desirably made, of conventional corrugated board, as shown in Fig. 5, comprises the usual conventional tubular side structure made up of a pair of opposed lateral side walls I and an inter-- vening front wall II, and a back wall 12. The tube is held assembled by a corner binding strip I3 connecting the edges of a side wall In and front wall II. I

Unitary with the respective side walls are corresponding rectangular end flaps M which are designated the inner flaps since they are folded inward first and are then overlapped by the-rectangular flaps l unitary with the respective front and back walls which are designated the outer flaps. l

The inner flaps are provided each with a pair of oblique closed-endedslots l6, each slot extending from a point'on theroot 0r fold edge I! of the inner flap I 4, which is spaced from the associated corner of the box.

Each of the outer end flaps I5 has an oblique corner fold line l8, extending at an angle corresponding to that of the associated slot. The oblique fold extends at an angle to register with the slot in the set up box as shown in Fig. 2. Desirably both the slot and the flap are at angles of degrees to the respective edges of the blank or box.

Each outer end flap l5 has a pair of notches I9 in its free edge 20, each of which notches extends across the end of the associated fold line I8. The fold line from the lateral edge of the flap to the notch is desirabl of length substantially equal to the length of the associated slot IS in the inner flap. The outer edge, 2| of the notch l9 desirably extends at right angles to the fold line l8. Its inner edge 22 desirably extends substantially at right angles to the free edge of the flap and the vertex of the notch is desirably rounded on a fairly large are as at 23.

Each slot I6 is desirably out on a straight line 24 at its inner side, that is, at the side nearer the root of the flap. Its outer side is desirably bowed outward at 25 between its ends, while its extremities are narrowed at 26 and .21.

The corner or looking tongues 28 being folded inward along the fold lines l8, obliquely across the corrugations c of the paper stock, it will follow that this tongue is resiliently biased to tend to return to the plane of the flap. Accordingly, in assembly of the box, as best shown in Fig. 2, the point of each tongue 28 will readily enter the median or wider portion of the associated slot l6 and as the outer flap is then pushed inward the tongue will frictionally engage the straight or outer side 24 of the slot and near the end of the insertion movement the edge 2| of the notch will ride along the extremity of the associated slot I6, and when the assembly is completed the root of the tongue will snugly engage and be gripped by the reduced ends 26, 21 of the slot IS. The locking tongue 28 will overlie the inner face of the inner flaps, as best shown in Fig. 4, against which it may be pressed. In the assembled box each notch [9 will thus straddle the associated inner flap at the inner edge of the corresponding slot IS, the edge 2| of the notch being in the inside of the box and the edge 22 and thegreater the weight the more secure the lock. The box bottom is at least as strong as the tensile strength of the board of which the box is made.

The box may be readily disassembled by simply grasping the exposed free edge of each outer flap and pulling outward to cause the corner tongues 28 to ride out of their respective slots 16.

It will be noted that the various flaps making up the bottom extend substantially in .a single plane and that a downward thrust upon this plane i ineffective to disengage the interlocking flaps thereof. Since all of the flaps making up the bottom extend substantially in a, single plane the structure lends itself readily to the application along the abutting edges of adhesive tape useful for shipping or mailing packages.

The box desirably has a pair of lateral short top flaps '29 unitary with the side walls In and a hinged cover 30 unitary with the rear wall l2, provided with a front flap 3| that has a wide short extension tongue 32 at its mid portion. The front wall has a pair of V notches 33, the points or vertices of which are aligned with the ends of the extension tongue 32. Accordingly, in i assembly, the ends of the cover flap 3| may be introduced in back of the'front wall ll, while the wide extension tongue 32 is allowed to protrude over the forward edge of the front wall so that when the box is closed each end of the extension tongue 32 engages the vertex of the corresponda ing V notch 33. width of the forward edge of the cover rests upon the upper edge of the front wall ll, so that the box will sustain a substantial weight, without the cover collapsing inward under weight resting upon the top of the box' as it might if the cover flap were wholly tucked inside the front wall of the box.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope of the claims, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent of the United States is: a

l. A rectangular collapsible box having side As a consequence, the major walls, a pair of opposed inner end flaps fold lines 7 notch in the free edge thereof extending across 7 the end of the corresponding oblique fold, each fold being equal in length to the length of the corresponding slot of the associated inner flap, said notch extending at its outer side at right angles to the length of the associated oblique fold, the inner side of each notch being substantially at right angles to the free edge of the I outer flap, the notch being rounded at its apex.

2. A rectangular collapsible box comprising side walls having a pair of opposed inner end flaps fold lines between said walls and said flaps and a pair of opposed outer end flaps, the inner end flaps having oblique slots therein extending from the fold line of the respective flaps obliquely inward, each of said flaps having a straight edge at the side adjacent its root, the outer side of said slot being bowed outwardly at the intermediate part of its length, said slot being of reduced thickness near its ends, the outer flaps having corner folds at angles corresponding to those of the slots and having notches at the free edges thereof which intersect the ends of the corresponding folds, whereby the tongues determined by said folds may be readily introduced in the assembly of the box into the bowed portion of the associated slot and the sides of said tongue will frictionally engage the end portions of said slot and the outer faces of the tongues will engage the respective straight edges of the slots, each tongue in the set up box lying over the inner face of the associated inner flap with the notch straddling the extremity of the corresponding slot.

3. A collapsible box of corrugated paper board having side walls, a pair of opposed inturned inner end flaps fold lines between said walls and said flaps, a pair of opposed inturned outer end flaps, the inner flaps having oblique closed slots therein converging from the corresponding fold lines and widened between the ends thereof, the outer flaps having oblique corner folds determining locking tongues, each corner fold extending at an angle corresponding to that of the associated slot, eachouter flap having a notchin' the freeedge thereof, across the inner end of.

each corner fold, the length of-the corner fold being equal to the length of the associated slot, the fold line extending obliquely across the corrugations andbeing resiliently biased toward the plane of the flap, whereby each corner tongue introduced into the corresponding slot will frictionally engage the outer edge and the ends of said slots, and in the completely set up box said tongues will lie flat upon the inner face of the associatedinner flaps with the notches straddling the inner ends of the respective slots.

4. A collapsible corrugated paper board box comprising side walls, a pair of opposed inturned inner end flaps. a pair of opposed inturned outer end flaps fold lines between said walls and said flaps, the corrugations extending at right angles to said fold lines, the inner end flaps having a pair of closed ended slots extending therealong from between the ends of the respective fold lines of said flaps at an angle of 45 degrees, said slots being straight along the inner sides and widened intermediate the ends thereof, but relatively narrow at their ends,'the outer flaps having oblique corner folds across the corrugations extending at an angle of 45 degrees, said outer flaps being notched at the free edges thereof across the ends of said folds, each notch having an outer side extending at right angles to the length of the fold and an inner side extending at nearly right angles to the free edge of the fold, said notches being rounded at the inner ends thereof, the length of each fold being substantially equal to the length of the associated slot, whereby each corner tongue will tend resiliently to flex toward the plane of the corresponding flap, so that upon tucking the tongue into the associated slot it will engage the outer straight edge of the slot and the lateral edges of the tongue will frictionally engage the ends of the slots, and in the assembled or set up box the notch will straddle the end of the slot.

SAMUEL L. COHEN.

MORTON J. MARGOLIES. 

